Research On Shafting Alignment Technology Considering Aft Stern Tube Bearing Incline And Ship Hull Deformation

Marine Propulsion Shafting is an important part of ship power system.With the development of cargo ships toward large-scale,the geometric scale of shafting and the weight of propeller are increasing,which makes the bearing to subject more load,so that bearings easy to wear and burn down during navigation.In addition,there may be many faults,such as gear improper engagement,abnormal vibration and so on.At present,domestic and foreign shipyards usually adopt rational alignment technology to solve the above problems,but there is still a lack of consideration for the influence factor of bearing inclination behind aft stern tube in the actual alignment calculation,and the influence of hull deformation is not fully understood,which lead to a large deviation between the actual shafting alignment effect and the theoretical alignment result.In order to improve the level of shafting alignment,the following series of studies have been carried out in this paper.In this paper,the rational calculation method of shafting alignment is studied.Firstly,the model of shafting alignment is established by ANSYS and the finite element analysis is carried out,combined with the technical process of shafting alignment.The principle of bearing influence number is expounded,and the optimal adjustment method of bearing displacement is put forward based on linear programming.Then,the second development of shafting alignment software based on VB.NET is carried out through Visual Studio platform,in order to realize the engineering application of the shafting alignment algorithm.Finally,the jacking measurement method and the dynamic measurement method based on strain gauge are analyzed to verify the reliability of the alignment calibration results.On this basis,combined with the force characteristics of aft stern tube bearing,this paper puts forward the general relationship of the definition of inclination,and establishes the design model of aft stern tube bearing and the bearing load influence model,and completes the calculation of shafting alignment with an example,considering the inclination of aft stern tube bearing based on the finite element method and transfer matrix method.In addition,the influence of hull deformation on shafting moment and bearing displacement is analyzed in this paper,and the mathematical expressions of shafting moment and bearing displacement in change are established.Combining with the critical displacement of bearing in the maximum hull deformation,the calculation of shafting alignment considering hull deformation is completed with an example.